Animal shoulder models are important in the investigation of the natural history of various pathologic conditions and for evaluation of the effectiveness of different treatments and biomaterials. The characteristics of animal shoulder models that may be used for rotator cuff related experiments are different with regard to the anatomy, behavioral pattern, advantages and disadvantages in application to each other. The lower primates and all the non-primate species, except the tree kangaroo, were neither functional overhead nor had a true rotator cuff. Utilizing more advanced primates, or perhaps even the tree kangaroo would be ideal and the most relevant to man as they possess a true rotator cuff. However, ethical concerns, costs, and many limitations in obtaining primates generally preclude the use of these animals for such research. Finally we should consider the differences in comparative anatomy and behavioral pattern of each ani-mal model during performance or interpretation of rotator cuff experiments.(Clin Shoulder Elbow 2015;18(1):52-58)